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United States Patent | 5,142,426 |
Re ,   et al. | August 25, 1992 |
A thin film magnetic head, having a predetermined cut-off frequency is constructed of alternating first and second layers, the first layers include a magnetic material and the second layers include a resistive material. The resistivity of the second layers is chosen so that the head's cut-off frequency exceeds the head's required frequency response. The resistivity of the second layers is chosen to be considerably less than any level of resistivity which falls within the insulation regime.
Inventors: | Re; Mark E. (Yorktown, NY); Russak; Michael A. (Brewster, NY); Webb; Bucknell C. (Croton-on-Hudson, NY) |
Assignee: | International Business Machines Corporation (Armonk, NY) |
Appl. No.: | 542288 |
Filed: | June 21, 1990 |
Current U.S. Class: | 360/126; 360/110; 360/120; 360/122 |
Intern'l Class: | G11B 005/147 |
Field of Search: | 360/110,119-126 |
4241367 | Dec., 1980 | Nomura et al. | 360/127. |
4277808 | Jul., 1981 | Nagaki | 360/113. |
4306215 | Dec., 1981 | Jeffers | 338/32. |
4489357 | Dec., 1984 | Von Ooijen et al. | 360/122. |
4651248 | Mar., 1987 | Shiiki et al. | 360/119. |
4799118 | Jan., 1989 | Yamada et al. | 360/125. |
4814921 | Mar., 1989 | Hamakawa et al. | 360/126. |
Foreign Patent Documents | |||
58-192311 | Nov., 1983 | JP | 360/110. |
62-257610 | Nov., 1987 | JP. | |
64-39608 | Feb., 1989 | JP. |
J. Appl. Phys., vol. 54, No. 7, pp. 4168-4173, Jul. 83, by Hughes, "Thin Film Recording Head Efficiency and Noise". J. S. Y. Feng et al., "Permeability of Narrow Permalloy Stripes", Transactions on Magnetics, vol. MAG-13, No. 5, Sep. 1977, pp. 1521-1523. Mee et al., "Magnetic Recording", McGraw-Hill Book Co., vol. 1, Technology, pp. 314-329. Lazzari et al., "Integrated Magnetic Recording Heads", IEEE Transactions on Magnetics, vol. MAG-7, No. 1, Mar. 1971, pp. 146-150. |
TABLE 1 __________________________________________________________________________ CUT-OFF FREQUENCY VS. RESISTIVITY f.sub.r (MHz) 10 20 30 40 50 100 300 1000 __________________________________________________________________________ W 3 .0003 .00066 .0010 .0014 .0017 .0035 .011 .036 (microns) 6 .0014 .0028 .0010 .0057 .0071 .0143 .043 .144 10 .0039 .0079 .012 .016 .020 .04 .12 .4 30 .036 .072 .11 .14 .18 .36 1.08 3.6 100 .40 .80 1.2 1.6 2.0 4.0 12.0 40. __________________________________________________________________________